CycleOps
ANT+ Speed or Cadence Sensor

Details

The CycleOps ANT+ Speed or Cadence Sensor accurately tracks your speed and cadence and is used along with a power meter or with an ANT+-compatible cycling computer (power meters and ANT+ computers sold separately). This unit easily attaches on the frame next to your left crankarm and rear wheel to monitor and display your cadence or speed on your cycling computer of choice.

I bought this sensor for indoor cycling, but his thing does not work, im sure my ant+ dongle is working, but zwift can't find it. I bought a garmin speed sensor, and it works fine, so just don't waste ur time and money, just go get a garmin